Electrical household appliance for preparing food comprising a safety device

ABSTRACT

The invention concerns a household appliance comprising a housing ( 1 ) containing a motor ( 3 ) whereof the output shaft rotates an implement ( 13 ) housed in a bowl ( 8 ) whereon is fixed a lid ( 15 ) including a tab ( 23 ); and a safety device comprising a sliding vertical plunger ( 29 ) actuated by a control button ( 33 ) mounted movable on the housing between an off-position and an on-position, means ( 50, 52 ) for locking the button ( 33 ) in off-position when the lid is not fixed on the bowl, and for unlocking said button ( 33 )when the lid is properly fixed on the such that the plunger ( 29 ) takes up a low position wherein it actuates a switch ( 27 ) to control the closure of the motor power supply, and retaining means ( 52, 54 ) co-operating with the lid tab ( 23 ) to prevent the latter from opening when the plunger ( 29 ) is in low position. The invention is characterized in that the safety device further comprises means ( 63 ) for maintaining the plunger ( 29 ) in low position when the switch ( 27 ) is locked in closed position.

The present invention relates to an electric household appliance for thepreparation of foodstuffs, such as for example a chopper, comprising ahousing enclosing an electric motor group whose output shaft projectsfrom the housing and is adapted to drive in rotation a working tooldisposed within a bowl on which is fixed a removable cover comprising atongue fixed on the periphery of the cover; and a safety devicecomprising a switch arranged in the electrical supply circuit of themotor, a control pusher for the switch vertically slidably mountedwithin and on the periphery of the housing, associated with a returnspring, and actuated by a manual control member fixedly connected to thepusher and movably mounted on the housing between a stop position and astart position, means permitting, on the one hand, locking the manualcontrol member in the stop position when the cover is not correctlyfixed on the bowl such that the pusher remains in an upper position inwhich it does not actuate the switch, and on the other hand, to unlockthis manual control member in the stop position when the cover iscorrectly secured on the bowl such that, by manipulating the controlmember toward its start position, the pusher slides to a lower positionin which it controls the closing of the switch to permit supply to themotor, as well as retaining means coacting with the tongue of the coverto prevent opening this latter when the pusher is moved toward its lowposition.

In known electric household appliances with manual control of this type,the safety device permits the starting of the apparatus by actuating themanual control member toward its start position only when the cover iscorrectly secured on the bowl, whilst preventing in the course ofoperation of the apparatus the opening of the cover thanks to theretaining means coacting with the tongue of the cover, therebypermitting protecting the user from any risk of harm which would be dueto the moving working tool, generally constituted by a slicing toolwhich is considered dangerous, if the apparatus were started when thecover is not correctly secured on the bowl or if the cover was removedin the case of operating the apparatus. At the end of preparing thefoodstuff, the pusher rises again to its upper position under the forceof its return spring, so that the switch leaves its open position to cutthe electrical supply to the motor, and the manual control member whichis fixedly connected to the pusher is then returned to the stop positionin which the cover can then be opened and removed.

Although such electric household appliances offer effective safety tothe user, there nevertheless remains the risk of harm to the user in thecase in which the switch is blocked in its closed position due forexample due to sticking of the fixed and movable contacts of the switch,or else to a fault in manufacture of the switch. Thus, in this case, thepusher rises under the action of its return spring, carrying with it themanual control member toward its stop position, and the cover can thenbe opened and removed; the motor being still supplied, the working toolcontinues to turn in the bowl without the cover, which is dangerous tothe user if he accidentally introduces his hand into the open bowl.

The invention has particularly for its object to overcome this risk andto provide an electric household appliance, of the type mentioned above,in which the safety device offers complete safety to the user.

According to the invention, the safety device comprises means permittingholding the pusher in the lower position when the switch is stuck in itsclosed position.

Thus, it will be understood that by preventing the pusher from rising toits upper position in the case in which the switch is stuck in itsclosed condition, the manual control member cannot then be broughttoward its top position, and it is hence impossible to take the coveroff the bowl. The user must then unplug the apparatus to stop the motorbefore proceeding to a subsequent disassembly of the appliance.

For a switch of the type comprising a body in which is verticallyslidably mounted a contact pusher which has two end positions,respectively upper and lower, projecting from the body, and whichcarries, adjacent its lower end, a metal ring serving as a movablecontact adapted to coact with two fixed contacts mounted on said body,and according to a preferred embodiment of the invention, the pusher ispermanently urged against the upper end of the contact pusher, and theholding means of the pusher in the lower position is constituted by afirst tongue fixedly mounted on the pusher and which permanently bearsagainst the lower end of the contact pusher.

Preferably, the pusher and the first tongue are made of a single pieceof plastic material.

Thus, this continuously urged tongue which is a permanent part of thepusher constitutes a simple member, inexpensive and easy to make,reliable, and completely adapted to mass production.

The characteristics and advantages of the invention will become furtherapparent from the following description, by way of non-limiting example,with reference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of an electric householdappliance according to the invention, showing the cover correctlysecured to the bowl and before starting the appliance; and

FIG. 2 is a view similar to FIG. 1, the apparatus being in operation andthe switch being held in its closed position.

The electric household appliance shown in FIGS. 1 and 2 is an electricchopper comprising a housing forming a base 1, enclosing an electricmotor group 3 whose output shaft 4 projects vertically from the uppersurface 6 of the housing 1. This housing 1 is surmounted by a removablebowl 8 adapted to contain the foodstuffs to be chopped and has on itsbottom wall 9 a vertical chimney 11 in which engages the output shaft 4of the motor 3. The bowl 8 houses a rotating working tool 13, such as aknife, which is fitted over the chimney 11 and which is coupled inrotation with the output shaft 4 of the motor 3.

The bowl 8 is closed by a removable cover 15 by means of a securementsystem of the bayonet type, of which one of the elements is designatedat 16 in FIGS. 1 and 2.

The upper edge 18 of the cover 15 bears a large tongue 20 directeddownwardly and outwardly relative to the bowl 8 and which itselfcarries, adjacent its lower free end 21, a lip 23 perpendicular to thistongue and directed outwardly. After securement of the cover 15 on thebowl 8 by rotation of the cover, the lip 23 is at a certain height abovethe upper surface 6 of the housing 1.

The housing 1 also encloses a safety device, designated by the generalreference numeral 25 in FIGS. 1 and 2, which comprises a switch 27,whose detailed structure will be explained later, arranged in a mannerknown per se in the electrical supply circuit of the motor 3, and acontrol pusher 29 for the switch which is mounted vertically slidably atthe periphery of the housing 1 being associated with a return spring 31,and which is actuated by a manual control member 33 fixedly connected tothe pusher 29 and movably mounted on the housing 1 between a stopposition (FIG. 1) and a slide position (FIG. 2).

In the embodiment shown in FIGS. 1 and 2, the pusher 29 is laterallyspaced from the switch 27 and is disposed in a vertical integral bulge35 that projects at the periphery of the housing 1, and whose upperportion 36 rises to a certain height above the upper surface 6 of thehousing 1.

In this embodiment, the manual control member 33 is a pushbuttonvertically mounted on the upper portion 36 of the bulge 35 of thehousing 1, in vertical prolongation from the pusher 29, and whichinternally carries a vertically downwardly extending lip 38 fixed on theupper vertical portion 40 of the pusher 29 by any appropriate securementmeans.

With respect to FIG. 1, the pushbutton 33 comprises, on its surfacedirected toward bowl 8, a slot 42 opening on one of the lateral sides ofthe pushbutton 33 and extending into this latter in a direction parallelto the upper surface 6 of the housing 1 by being located at the sameheight above the upper surface 6 of the housing as the lip 23 of thecover 15. In the correct connecting position of the cover 15 on the bowl8, the lip 23 is engaged in the slot 42 of the pushbutton 33, as shownin FIGS. 1 and 2.

As is seen in FIGS. 1 and 2, the return spring 31 of the pusher 29 isinterposed between a horizontal bearing surface 44 formed in the housing1, adjacent the bottom wall 45 of this latter, and a small horizontalT-shaped wing 47 formed on the lower vertical portion 48 of the pusher29.

The safety device 25 comprises means permitting locking the pushbutton33 in the stop position when the cover 15 is not correctly connected tothe bowl 8, which is to say when the lip 23 of the cover 15 is notengaged in the slot 42 of the pushbutton 33. In one embodiment, theblocking means are constituted by a lock, shown schematically at 50 inFIG. 1, mounted resiliently on the upper portion 40 of the pusher 29 andadapted itself to block the pushbutton 33 relative to the upper edge 52of the bulge 35 of the housing 1. The pushbutton 33 in stop positionbeing thus locked when the cover 15 is not correctly secured on the bowl8, it is impossible for the user to push the pushbutton downwardly.

Such that the pusher 29 is not actuated and hence remains in a raisedrest position in which it does not actuate the switch 27.

These locking means of the pushbutton 33 also constitute meanspermitting unlocking this pushbutton 33 in the stop position when thecover 15 is correctly connected to the bowl 8, which is to say when thelip 23 of the cover is engaged in the slot 42 of the pushbutton 33, asshown in FIG. 1. Thus, upon this engagement of the tongue 23 of thecover 15 in the slot 42 of the pushbutton, the lip 23 acts on the lock50 to disengage it sufficiently from the upper edge 52 of this bulge 35of the housing 1, such that the pushbutton 33 will be freed. Thepushbutton 33 in stop position being thus unlocked, the user can pushdown the pushbutton, in the direction of the arrow F in FIG. 1, whichpasses then from the start position and which involves a sliding of thepusher 29 toward a low working position in which it actuates the switch27 to control the closure of the electrical supply circuit of the motor3, as shown in FIG. 2.

The safety device 25 also comprises a retaining means coacting with thelip 23 of the cover 15 to prevent opening of this latter when the pusher29 is moved toward its lower position by manipulating pushbutton 33, thecover 15 being correctly secured to the bowl 8. In the embodiment shownin FIGS. 1 and 2, these retaining means are constituted by an upper edge54, in the shape of a notch, of the slot 42 of the pushbutton 33 whichholds the lip 23 of the cover 15 against the upper edge 52 of the bulge35 of the housing when the user pushes down the pushbutton 33, as shownin FIG. 2.

According to the invention, the safety device comprises means permittingholding the pusher 29 in its lower position when the switch 27 (FIG. 2)is held closed.

With respect to FIGS. 1 and 2, the switch 27 comprises a body 55 inwhich is slidably mounted a vertical contact pusher 56 which has twofree ends, respectively an upper end 56 a and a lower end 56 b,projecting from the body 55, and which carries, adjacent its lower end56 b, a metallic ring 58 fixed by crimping and serving as a movablecontact adapted to coact with two fixed contacts 60, 61 slightly turnedtoward each other and mounted externally on a lower surface of the body55.

In the embodiment shown in FIGS. 1 and 2, the holding means for thepusher 29 in its lower position, when the switch 27 is stuck in itslower position (FIG. 2) as a result for example of sticking of the metalring 58 to the two fixed contacts 60, 61, are constituted by a firstholding tongue 63 which is fixedly mounted on the pusher 29 and whichpermanently bears on the lower end 56 b of the contact pusher 56 of theswitch 27.

As shown in FIGS. 1 and 2, the pusher 29 also permanently bears on theupper end 56 a of the contact pusher 56 of the switch 27 by means of asecond actuating tongue 65 also fixedly mounted on the pusher 29.

Thus, the sliding pusher of contact 56 of the switch 27 is maintainedpermanently by its two ends against the two tongues 63, 65 of the pusher29, such that it always follows the sliding movement given to the pusher29.

Preferably, the pusher 29 and its two tongues respectively the holdingtongue 63 and the actuating tongue 65, are molded as a single piece ofplastic material.

As shown in FIGS. 1 and 2, the two tongues 63, 65 of the pusher 29 arestraight, extending parallel to each other, and are each mounted inT-shaped relation on this pusher 29, thereby constituting a fork withtwo teeth between which is mounted in bearing relationship the verticalcontact pusher 56 of the switch 27.

Thus, when the cover 15 is correctly secured to the bowl 8, which is tosay when the lip 23 of the cover 15 is engaged in the slot 42 of thepushbutton 33 (FIG. 1), the user can push the pushbutton 33 which passesfrom its start position in which the upper edge 54 of the slot 42 of thepushbutton maintains the lip 23 of the cover 15 bearing against theupper edge 52 of the bulge 35 of the housing (see FIG. 2), therebypreventing opening the cover 15, and, simultaneously, the pusher 29moves downwardly against the return spring 31; in the course of thismovement of the pusher 29, the tongue 65 of the latter, bearingpermanently on the upper end 56 a of the contact pusher 56 of the switch27, slides this contact pusher 56 downwardly, whose metallic ring 58then co-acts with the two fixed conduits 60, 61 so as to close theswitch 27 for controlling the electrical supply to the motor 3 (FIG. 2),whilst the tongue 63 of the pusher 29, continuously bearing on the lowerend 56 b of the contact pusher 56, moves downwardly to the same heightas the contact pusher 56.

If now the switch 27 is blocked in its closed condition, FIG. 2, thepusher 29 remains held in lower position thanks to its holding tongue 63coacting with the lower end 56 b of the contact pusher 56 thus blocked,such that the pushbutton 33 secured to the pusher 29 also remains downin its start position in which it prevents the opening of the cover 15.The user must then unplug the apparatus to stop the motor 3.

There is thus provided according to the invention an electricalhousehold appliance with manual control provided with a safety devicewhich is particularly advantageous both from the point of view of itssimplicity of manufacture and from the point of view of the optimumsafety which it offers to the user both when the cover is not correctlysecured on the bowl, and when the apparatus, with the cover correctlysecured on the bowl, is in normal or accidental operation because of ablocking of the switch in its closed position.

It will be noted that the above description has been given withreference to a safety device for a slicer with a rotating knife. Ofcourse, this safety device is applicable to any other electric householdappliance for food preparation with manual control comprising a rotatingworking tool that is considered dangerous, such as for example a kitchenrobot using various rotatable slicing tools.

What is claimed is:
 1. Electric household appliance for the preparationof foodstuffs, comprising a housing (1) supporting a bowl (8) on whichis secured a removable cover (15) comprising a lip (23) fixed on theperiphery of the cover; said housing enclosing an electric motor group(3) whose output shaft (4) projects from the housing and drives inrotation a working tool (13) disposed in said bowl; and a safety device(25) comprising a switch (27) arranged in the electrical supply circuitof the motor, a pusher (29) for controlling the switch verticallyslidably mounted within and at the periphery of the housing (1),associated with a return spring (31), and actuated by a manual controlmember (33) fixably connected to the pusher (29) and movably mounted onthe housing (1) between a stop position and a start position, means (50,52) permitting on the one hand locking the manual control member (33) inthe stop position when the cover (15) is not correctly connected to thebowl (8) such that the pusher (29) remains in an upper position in whichit does not actuate the switch (27), and on the other hand unlockingthis manual control member (33) in the stop position when the cover (15)is correctly fixed on the bowl (8) such that, by manipulating thecontrol member (33) toward its start position, the pusher (29) comes tooccupy by sliding a lower position in which it controls the closure ofthe switch (27) to permit supply to the motor, as well as retainingmeans (52, 54) coacting with the lip (23) of the cover (15) to preventopening this latter when the pusher (29) is moved to its lower position,characterized in that the safety device (25) comprises means (63)permitting holding the pusher (29) in its lower position when the switch(27) is blocked in its closed condition.
 2. Electric household applianceaccording to claim characterized in that the switch (27) comprising abody (55) in which is slidably mounted a vertical contact pusher (56)which has two free ends, respectively an upper end (56 a) and a lowerend (56 b), projecting from the body (55), and which carries, adjacentits lower end (56 b), a metallic ring (58) serving as a movable contactadapted to coact with two fixed contacts (60, 61) mounted on said body(55), the pusher (29) bears permanently on the upper end (56 a) of thecontact pusher (56), and the means for holding the pusher (29) in itslower position are constituted by a first tongue (63) fixedly mounted onthe pusher (29) and which continuously bears on the lower end (56 b) ofthe contact pusher (56).
 3. Electric household appliance according toclaim 2, characterized in that the pusher (29) is laterally spaced fromthe body (55) of the switch (27) and permanently bears on the upper end(56 a) of the contact pusher (56) by means of a second tongue (65)fixedly mounted on the pusher (29).
 4. Electric household applianceaccording to claim 3, characterized in that the pusher (29) and thesecond tongue (65) are made of a single piece of plastic material. 5.Electric household appliance according to claim 2, characterized in thatthe pusher (29) and the first tongue (63) are made of a single piece ofplastic material.
 6. Electric household appliance according to claim 4,characterized in that the first (63) and second (65) tongues arestraight, extending parallel to each other, and are each mounted inT-shaped relation on the pusher (29).
 7. Electric household applianceaccording to claim 3, characterized in that the first (63) and second(65) tongues are straight, extending parallel to each other, and areeach mounted in T-shaped relation on the pusher (29).
 8. Electrichousehold appliance according to claim 6, characterized in that thepusher (29) is laterally spaced from the body (55) of the switch (27)and permanently bears on the upper end (56 a) of the contact pusher (56)by means of a second tongue (65) fixedly mounted on the pusher (29). 9.Electric household appliance according to claim 8, characterized in thatthe pusher (29) and the second tongue (65) are made of a single piece ofplastic material.